Recently, facilities of a subminiature base station (femtocell base station) according to a femtocell system are developed. Further, it is technically possible to establish a base station that can be connected to the Ethernet line or a broadband line. An amendment to relevant bills is prepared in Japan. If amending the relevant bills, a user in a general household can purchase a femtocell base station by electronics retail stores and the femtocell base station can be set at an arbitrary place of a home or office, thereby using it.
The following technique is disclosed in Japanese Laid-open Patent Publication No. 2006-217443. In the case that a call request was received from a mobile station, a location area of a transmission destination is specified by a general phone number of the transmission destination, a distance segment from the mobile station of a transmitting source to the mobile station of the transmission destination is obtained from charging information for calculating call charges, a call charge unit in a communication system of each phone number of the transmission destination is calculated on the basis of the distance segment, the current time, and subscription condition information and the lowest call charge system is selected from among the call charge unit.
The following technique is disclosed in Japanese Laid-open Patent Publication No. 9-18963. At the outgoing call from a PHS terminal, subscriber identification information to be sent from the PHS station is transmitted to a PHS management center with a D-channel packet on an I′ line and is then authenticated at a PHS base station. And, after obtaining the authentication result, the call from the PHS terminal is transmitted via an analog line or the I′ line at the PHS base station, thereby selecting a communication carrier with the lowest costs.
Since it is assumed that a communication service is provided on the unit basis of a communication carrier over a system having the conventional femtocell base station, a user of the femtocell base station cannot select a connection to a core network of an arbitrary communication carrier from the femtocell base station.
Therefore, when differing communication carriers subscribed by the user of the femtocell base station in each general household or office, the femtocell base station can be used only a user having a terminal of a communication carrier dependent on the set femtocell base station. When the user changes the communication carrier, the user cannot apply the femtocell base station of the communication carrier before the change thereof.